Heat Transfer Enhancement of Different Channel Geometries Using Nanofluids and Porous Media

In this study, natural convection of heat transfer in various channel geometries with a constant surface area under laminar flow condition has been investigated numerically. Various hot surface temperatures (Th = 35-95°C) have been applied on the surfaces of the channels to investigate four different geometries of annular channels (Circular (C), Square (S), Elliptic (E) and Airfoil (F)) on the heat transfer rate. Once the optimum geometry was exhibited, the effect of three nanofluids (Al2O3/water, CuO/water and SiO2/water) is investigated in the analysis and compared to pure water to enhance the convective heat transfer of the base fluid. Moreover, with these nanofluids, analysis has been performed for three different volume concentrations of nanoparticles of Ø = 2%, 4% and 6% along with 0% (pure water). Porous foams (ε = 0.9 to 0.99) were used in addition to nanofluids to see if heat transfer could be improved. Results indicate that the heat transfer rate was greatly increased when the airfoil geometry was used, with a maximum and minimum increase in heat transfer coefficient of 60% and 46%, respectively. Also, higher nanoparticle of Al2O3 dispersion to the base fluid enhances the heat transfer rate by 15% compared to other nanofluids.

Investigation of High Sensitivity Piezoresistive Pressure Sensors for -0.5…+0.5 kPa

The investigation of the pressure sensor chip’s design developed for operation in ultralow differential pressure ranges has been conducted. The optimum geometry of a membrane has been defined using available technological resources. The pressure sensor chip with an area of 6.15х6.15 mm has an average sensitivity S of 34.5 mV/кPa/V at nonlinearity 2KNL = 0.81 %FS and thermal hysteresis up to 0.6 %FS was created. Owing to the chip connection with stop elements, the burst pressure reaches 450 кPa.

Investigation of High Sensitivity Piezoresistive Pressure Sensors for -0.5…+0.5 kPa

The investigation of the pressure sensor chip’s design developed for operation in ultralow differential pressure ranges has been conducted. The optimum geometry of a membrane has been defined using available technological resources. The pressure sensor chip with an area of 6.15х6.15 mm has an average sensitivity S of 34.5 mV/кPa/V at nonlinearity 2K_NL = 0.81 %FS and thermal hysteresis up to 0.6 %FS was created. Owing to the chip connection with stop elements, the burst pressure reaches 450 кPa.

Investigation of High Sensitivity Piezoresistive Pressure Sensors for -0.5…+0.5 kPa

The investigation of the pressure sensor chip’s design developed for operation in ultralow differential pressure ranges has been conducted. The optimum geometry of a membrane has been defined using available technological resources. The pressure sensor chip with an area of 6.15х6.15 mm has an average sensitivity S of 34.5 mV/кPa/V at nonlinearity 2K_NL = 0.81 %FS and thermal hysteresis up to 0.6 %FS was created. Owing to the chip connection with stop elements, the burst pressure reaches 450 кPa.

Investigation of High Sensitivity Piezoresistive Pressure Sensors for -0.5…+0.5 kPa

The investigation of the pressure sensor chip's design developed for operation in ultralow differential pressure ranges has been conducted. The optimum geometry of a diaphragm has been defined using available technological resources. The pressure sensor chip with an area of 6.15 × 6.15 mm has an average sensitivity S of 34.5 mV/ κPa/V at nonlinearity 2K NL = 0.81 %FS and thermal hysteresis up to 0.6 %FS was created. Owing to the chip connection with stop elements, the burst pressure reaches 450 κPa. The developed pressure sensor can be used in medicine, automotive industry and highly specialized scientific developments.

The Tool’s Optimum Geometry Research for Obtaining Apertures in Semi-Cured Polymer Composite Materials

The composite materials features and characteristic defects in the obtaining apertures by machining are considered. A new method for forming apertures in fibrous polymer composite materials is proposed. The optimal shape of a tool for piercing holes is determined. The profiles of the pointed part of the tool are compared using numerical modeling.

Design Optimisation of Labyrinth Seals using LES

Labyrinth seals are extensively used in gas turbines to control leakage between components. In this research, the effects of geometry on the sealing performance are investigated. To obtain the best sealing performance, an investigation is undertaken into the possibility of optimising labyrinth seal planforms using a genetic algorithm (GA). Large Eddy Simulation (LES) is used for its ability to accurately capture the complex unsteady behaviour of this type of flow. Three hundred LES calculations are carried out. By making use of a large number of processors, an optimum geometry can be achieved within design cycle timescales. The optimised design shows a leakage reduction of about 27.6\% compared to the baseline geometry. An immersed boundary method (IBM) is used with LES to generate complex geometries on a background Cartesian grid. The GA is inherently parallel, and this enables the exploitation of the reliability and accuracy benefit of LES as demonstrated.